The purpose of variable direction of view endoscopes is to provide greater viewing mobility. Variable direction of view endoscopes come in two general classes: rigid and flexible. Rigid variable direction of view scopes either change their line of sight mechanically, as disclosed in U.S. Pat. No. 3,856,000 to Chikama, U.S. Pat. No. 6,371,909 to Hoeg, U.S. Pat. No. 6,560,013 to Ramsbottom, U.S. Pat. No. 4,697,577 to Forkner, U.S. Pat. No. 6,500,115 to Krattiger et al., and U.S. Pat. No. 5,762,603 to Thompson, or electronically, as disclosed in U.S. Pat. No. 5,313,306 to Kuban, and U.S. Pat. No. 5,800,341 to McKenna et al. Flexible variable direction of view endoscopes, exemplified by U.S. Pat. No. 3,572,325 to Bazell et al., change their line of sight by deflecting the entire distal section of the instrument.
A problem introduced by such variable direction of view endoscopes is that the endoscopic line of sight can not readily be estimated during use because the tip of the endoscope is hidden. Fixed-angle endoscopes do not suffer from this problem because the viewing direction has a fixed relationship to the endoscope shaft and can be mentally extrapolated by the operator as an extension of the endoscope's longitudinal axis. Even with indicator knobs, dials, or markers (as in U.S. patent application 20020099263 and U.S. Pat. No. 6,500,115 to Krattiger et al.) it can be difficult to estimate viewing direction of variable direction of view scopes because the position of the view vector origin is unknown. Getting an external estimate of where the endoscope is “looking” is important as the clinician tries to integrate preexisting knowledge of the anatomy with the viewing process, and this need must somehow be met.
Hale et al. in U.S. Pat. No. 6,663,559 take a step in this direction by providing a computer graphical depiction of a variable direction endoscope and its viewing direction to assist the user in understanding the changing viewing configuration. This depiction is meant to show the dynamic relationship between the shaft and the endoscopic line of sight as it might be seen from an external viewpoint if the endoscope tip were visible during use. While this method gives the operator a view vector direction locator, it does not provide a clear correlation between the live image, its orientation, and the endoscope configuration.
Accordingly, the primary object of the present invention is to provide a dynamic representation of the endoscopic viewing direction featuring a live image icon and a virtual world. Another object is to provide real time numerical indications of the global position of the view relative to a defined equator and zero-meridian. Still further objects and advantages will become apparent from the ensuing description and drawings.